A self-leveling repair underlayment used for repairing and finishing gypsum and wood substrates above grade prior to the installation of new floor covering. When mixed with water, it produces a pourable or pumpable liquid compound that seeks its own level and produces a smooth, flat, hard surface. ARDEX GS-4 hardens and dries fast without shrinking, cracking or spalling. It can be walked on after 3 hours, and floor covering can be installed as soon as the underlayment has dried sufficiently for the floor covering selected. ARDEX GS-4 can be installed from 1/4” up to 2” neat, and can also be tapered to 1/16” to match existing elevations. ARDEX GS-4 canbe installed up to any thickness with the addition of 1/8 - 1/4” washed, dried and properly graded pea gravel at ratio of up to 1:1 by volume. Coverage: (50 lb. bag) Approx. 22 sq. ft. at 1/4” thickness.